The invention relates generally to urethral prostheses and methods of insertion into a body. More particularly, the invention relates to a urethral prosthesis having a bladder/prostate segment and a penile urethra segment connected by a bridge segment, which crosses the urinary sphincter.
Urinary retention in males is often caused by neurological disorders or by obstructions in the urinary tract. Neurogenic urinary retention is a condition in which a person is unable to empty his urinary bladder voluntarily due to a neurological dysfunction of the urinary bladder and/or of the urinary sphincter. Neurogenic urinary retention is due to an inability of the bladder to contract and/or of the urinary sphincter to relax. Patients with spinal cord injuries, multiple sclerosis, Parkinson""s disease, or trauma to the pelvic region may suffer from neurogenic urinary retention on a permanent or transient basis.
Patients suffering from neurogenic urinary retention generally have limited options for draining their bladders. These include using a Foley catheter, intermittent catheterization, and a suprapubic drainage tube. All three options have high infection rates, are inconvenient for the patient and/or care giver, are uncomfortable for the patient, and cause the patient emotional distress.
Urinary retention is also caused by obstructions in the urethra, such as prostatic obstructions. The prostate gland encircles the urethra immediately below the urinary bladder. A common affliction among older males is benign prostatic hyperplasia (BPH), or the nonmalignant enlargement of the prostate. When the prostate becomes enlarged, it may restrict the urethra and thereby obstruct the flow of urine from the bladder.
A common treatment of BPH is surgical resection of the prostate and urethral tissue, but this option is not suitable for many patients. BPH afflicts primarily older males, so other health problems, such as cardiovascular disease, may prevent surgical intervention. Furthermore, potential complications associated with surgery, such as urinary infection, dysuria, and incontinence, may make a patient unwilling to undergo the surgery.
It is an object of the invention to relieve the symptoms of urinary retention in males without the high infection rates and other potential complications associated with current treatments. It is another object of the invention to provide a urethral prosthesis that resides within a bladder and urethra of a patient and that provides the patient control over drainage of the bladder without the discomfort and emotional distress associated with conventional treatments.
In one aspect, the invention relates to a urethral prosthesis including a first tubular element, a second tubular element, a bridge segment for joining the first and second tubular elements, and a valve. The first tubular element includes a distal portion with a drainage hole for receiving urine, a proximal end and a lumen, which extends from the drainage hole through the first tubular element to the proximal end of the first tubular element. At least a portion of the first tubular element is adapted for residing in a urethra of a patient. The second tubular element is adapted for residing in a penile urethra of a patient. The second tubular element includes a lumen extending from the bridge segment to its proximal end. The bridge segment has a diameter that is smaller than the diameter of the first tubular element and has a lumen for providing a permanent urine flow channel from the first tubular element through the urinary sphincter. The valve is disposed within the lumen of the second tubular element for controlling a flow of urine through the lumen of the second tubular element.
Embodiments according to this aspect of the invention can include the following additional features. The first and second tubular elements and the bridge segment may all be made of a pliable, biocompatible material, such as silicone rubber, for example. In another embodiment, the bridge segment comprises a spring disposed within the pliable, biocompatible material. In another embodiment, the proximal end of the second tubular element contains a suture wire to aid in removing the prosthesis from the urethra of a patient. The first and second tubular elements may also have an external surface coated with a coating including a plurality of gas bubbles therein.
In this aspect of the invention, the valve may be a magnetically-actuatable valve. In this embodiment, the valve includes a ferromagnetic valve seat, which has an aperture for the passage of fluid therethrough, and a valve element. The valve element includes a magnet encapsulated in a non-magnetic capsule. The capsule has a top portion and a base portion, which is wider than the top portion. The valve element is magnetically attracted to the valve seat so that it blocks the flow of fluid through the aperture in the valve seat.
In a second aspect, the invention relates to a urethral prosthesis including a first tubular element, a second tubular element, and a bridge segment of suture wires connecting the first and second tubular elements. The bridge segment resides within the urinary sphincter. The first tubular element has a drainage hole for receiving urine in its distal portion, a lumen extending from the drainage hole to its proximal end, and an external surface coated with a coating including a plurality of gas bubbles disposed therein. The first tubular element is adapted for residing at least partially in the urethra of a patient. The second tubular element is adapted for residing in a penile urethra of the patient and has a lumen.
Embodiments according to this aspect of the invention can include the following additional features. The second tubular element may also have an external surface coated with a coating including a plurality of gas bubbles. The first and second tubular elements may be composed of a pliable, biocompatible material, such as silicone rubber, for example. The second tubular element may include a suture wire attached to its proximal end to aid in removing the prosthesis from the patient. Finally, the second tubular element may include an optical lens embedded in its wall.
In a third aspect, the invention relates to a urethral prosthesis including a first tubular element, a second tubular element, and a bridge segment of suture wires connecting the first and second tubular elements. The bridge segment resides within the urinary sphincter. The first tubular element has a drainage hole for receiving urine in its distal portion, and a lumen extending from the drainage hole to its proximal end. The first tubular element is adapted for residing at least partially in the urethra of a patient. The second tubular element is adapted for residing in a penile urethra of the patient and has a lumen and includes an optical lens embedded in its wall.
Embodiments according to this aspect of the invention can include the following additional features. The first and second tubular element may also have an external surface coated with a coating including a plurality of gas bubbles. The first and second tubular elements may be composed of a pliable, biocompatible material, such as silicone rubber, for example. The second tubular element may include a suture wire attached to its proximal end to aid in removing the prosthesis from the patient.
The invention also relates to systems and methods for treating urinary retention. A system of the invention includes a urethral prosthesis of any of the above-described embodiments, an inflation cannula, and an inflatable balloon. The inflation cannula includes a lumen, which is in communication with the inflatable balloon for passage of fluid or gas to the balloon, so as to inflate the balloon. In one embodiment, the balloon covers at least a portion of the first tubular element when inflated. In another embodiment, the balloon covers the second tubular element when inflated.
A method of using such a system in which the balloon covers at least a portion of the first tubular element includes inserting the prosthesis in a urethra of a patient, pushing the prosthesis within the urethra so that the drainage hole is positioned in a bladder of the patient, delivering a volume of fluid or gas to the balloon through the inflation cannula so as to inflate the balloon, and withdrawing the prosthesis until a resistance is felt. This resistance indicates that the bridge segment of the prosthesis is positioned within the urinary sphincter.
A method of using such a system in which the balloon covers the second tubular element includes inserting the prosthesis in a urethra of a patient, pushing the prosthesis within the urethra until a first resistance is felt, delivering a volume of fluid or gas to the balloon through the inflation cannula so as to inflate the balloon, and pushing the prosthesis farther into the urethra until a second resistance is felt. This second resistance indicates that the bridge segment of the prosthesis is positioned within the urinary sphincter of the patient.
In an alternative embodiment of the method, the first and/or second tubular elements have an external surface coated with a coating including a plurality of gas bubbles. The method then further includes imaging the first and/or second tubular elements by ultrasound.
In alternative embodiments of the systems described above, a transducer is disposed within the balloon. A method of using such a system in which the balloon covers at least a portion of the first tubular element includes the steps of inserting the prosthesis in a urethra of a patient, pushing the prosthesis within the urethra so that the drainage hole is positioned in a bladder of the patient, delivering a volume of fluid or gas to the balloon through the inflation cannula so as to inflate the balloon, and withdrawing the prosthesis until a marked increase occurs in the pressure. This marked increase in pressure indicates that the bridge segment of the prosthesis is positioned within the urinary sphincter.
A method using such a system in which the balloon covers the second tubular element includes the steps of inserting the prosthesis within a urethra of a patient, pushing the prosthesis within the urethra until a first resistance is felt, delivering a volume of fluid to the balloon via the inflation cannula, monitoring a pressure of the balloon via the transducer, and pushing the prosthesis farther into the urethra until a marked increase occurs in the pressure. This marked increase indicates that the bridge segment is positioned within the urinary sphincter.
Methods of inserting a urethral prosthesis using such a system include inserting the urethral prosthesis into a urethra of the patient, pushing the prosthesis within the urethra until a first resistance is felt, delivering a volume of fluid via the inflation cannula to the inflatable balloon, so as to inflate the balloon, and pushing until a second resistance is felt. In an alternative embodiment, pressure in the balloon is monitored via a transducer, which is disposed within the balloon.
In an alternative embodiment of the above method, the first and/or second tubular elements have an external surface coated with a coating including a plurality of gas bubbles. The method then further includes imaging the first and/or second tubular elements by ultrasound. In an additional alternative embodiment, a transducer is inserted within the lumen of the second tubular element of the prosthesis for imaging the prosthesis by ultrasound and confirming that the bridge segment is properly positioned so that it spans the urinary sphincter. The ultrasound transducer may also be advanced into the lumen of the first tubular element after passing through the bridge segment, so as to confirm placement of the drainage hole in the bladder.
Another method of inserting a urethral prosthesis includes inserting a urethral prosthesis of any of the above-described embodiments into a urethra of a patient until the drainage hole of the first tubular element resides in the bladder and withdrawing the prosthesis until a resistance is felt. Embodiments of this method can include the following additional features. The external surface of the first and/or second tubular elements include an external surface coated with a coating including a plurality of gas bubbles. The method then further includes imaging the first and/or second tubular elements by ultrasound. In an additional alternative embodiment, a transducer is inserted within the lumen of the second tubular element of the prosthesis for imaging the prosthesis by ultrasound and confirming that the bridge segment is properly positioned so that it spans the urinary sphincter. The ultrasound transducer may also be advanced into the lumen of the first tubular element after passing through the bridge segment, so as to confirm placement of the drainage hole in the bladder.
Another method of inserting a urethral prosthesis includes inserting a urethral prosthesis of any of the above-described embodiments into a urethra of a patient and viewing the bridge segment of the prosthesis with an optical lens, so as to position the bridge segment within the urinary sphincter of the patient. In an alternative embodiment, the method also includes irrigating the urethra.
In other alternative embodiments of the method, the optical lens is an endoscope. The endoscope can be adapted for sliding within an external groove of the second tubular element. Also, the optical lens may be adapted for passing through the lumen of the second tubular element. Alternatively, the optical lens may be embedded within a wall of the second tubular element. Finally, the external surface of the first and/or second tubular elements include an external surface coated with a coating including a plurality of gas bubbles. The method then further includes imaging the first and/or second tubular elements by ultrasound. In an additional alternative embodiment, a transducer is inserted within the lumen of the second tubular element of the prosthesis for imaging the prosthesis by ultrasound and confirming that the bridge segment is properly positioned so that it spans the urinary sphincter. The ultrasound transducer may also be advanced into the lumen of the first tubular element after passing through the bridge segment, so as to confirm placement of the drainage hole in the bladder.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.